Transmission Speed Sensors

Transmission speed sensors are used to perform a contactless scan of a gear or trigger wheel in the transmission and generate an electronic digital signal proportional to the speed of rotation. There are commonly two-speed sensors that work in conjunction to provide accurate transmission data to the vehicle’s (ECM) engine control module or (TCM) transmission control unit.

Common symptoms of a faulty sensor include:

• Harsh or irregular shifting
• Cruise control inoperative
• Check engine light illuminated
• Speedometer inoperative

Transmission speed sensors can malfunction for a number of reasons including:

• Physical damage to the sensor
• Poor connection between the connector plug and sensor
• Corrosion
• Electrical failure